AboutRalph Salier-Hellendag Expertise Science Fair Judge for many years and experience with robotics, biology, chemistry, industrial processes, metalurgy and metal forming.
Experience Science Fair Judge for many years and have helped several students get to state level competition. Most recently 2 of my students received state level awards and one went on to the nationals in Washington DC.
Education/Credentials BA Archaeology - Anthropology
MA Business Anthropology
Question I am doing a project on tooth enamel and acids in the food we eat. so, first of all i don't know how to explain the words LACTIC, ACID, ACETIC, PHOSPHORIC, and CITRIC to a bunch of 3rd graders. Any suggestions? I know that acid eats calcium. I know that tooth enamel and eggshells are mostly calcium. My hypothesis is lactic acid eats tooth enamel faster than acetic, phosphoric, and citric acid because lactic acid is what is made by the s.mutans in your mouth. is it true that s mutans mix with saliva and glucose (i think that its your blood sugar) to make plaque and then the plaque uses even more sugar from your food to turn it into lactic acid? Is that the only acid that plaque turns sugar into? And what is the deal with weak and strong acids? is it the weaker the acid the more calcium it eats and opposite for the stronger acid? I looked on the internet and found that I couldn't use my baby teeth for the experiement but i could use eggs. The eggshell is the tooth enamel and I put the eggs in 8oz of yogurt, 8oz of pickle juice, 8oz coca-cola, and 8oz freshly squeezed orange juice. I also have one in water to show what no acid will do to your enamel. I'm keeping them at room temperature because i cant get the house as hot as our mouth. They really smell. What is the temperature of our teeth? I can see which one started damaging the egg first (the pickle juice) but how can i measure/compare the changes? I used the measuring tape to measure the size before the test began but eggshell is not that thick so I need another way of measureing the damage. I guess I am comparing time by taking pictures at the first sign of any changes (4 hours later) and everyday after that. can you please help? I don't know if i am doing this right.
Answer Hi Victoria,
You are making things a bit hard on yourself. Here are some suggestions
Get an evelope scale which weighs in grams and then using the egg shell (cleaned and washed and dry) weigh the same amount of shell for each of the test units. Then, obtain from a druggest the following items, distilled water (ph is neutral), Lactic Acid powder, Acetic acid, Citric acid. Phosphoric acid may be problematical since the drug store probably won't have it but you can ask. I am recommending this because it will be in a pure form and will disolve easier at a known acidic value. Besure that you also measure the ph for each and record t his as part of your experiment. You can use ph paper or a ph meter for this. You can get a ph meter from a garden supply or green house store for measuring the ph of soil. Will work for this too.
Once you have each of the liquids prepared (all should be clear) you can then carefully punch a hole in each egg shell peice and string it like beads and suspend this int the liquid to ensure complete exposure. You may need to put a knot between each peice so that it is not covered by another bit of shell. Before putting these strings of shell into the liquid, weight them and mark the end of the string with the weight dry and the liquid name. Then, using water wet the "assembly" and reweigh to get a wet weight. Then place the stringed shell (assemblys), one for each type of liquid, into the liquids. Be sure to anchor the end of the string on the side of the glass to make it easier to take them out to weigh.
Then once a day, take them out and weight them (wet) and keep a record to show how each looses weight over time. This can then be graphed. You should also take pics of each assembly at the start and 1/2 way through and at the end to show the progression.
